ZANZIBAR, Tanzania (AP) — The killing of seven Tanzanian peacekeepers in Sudan’s western region of Darfur is “shocking to Tanzania, ” the country’s deputy foreign minister said Sunday, as news of the attack spread across the East African country that has recently become more active in regional peacekeeping efforts.

Tanzanian officials do not yet have full details of the ambush Saturday in which 17 others were also wounded in the deadliest single attack on international peacekeepers in Sudan, said Mahadhi Juma Maalim on Sunday.

“Tanzania is saddened by this attack that led to (the) killings of our soldiers who went there to keep peace,” Maalim aid. “It’s shocking to Tanzania and members of the family of soldiers killed in Darfur.”

The Tanzanian government is studying the situation in Darfur and will notify families of the slain soldiers, said Maalim.

The assault by a large group of gunmen included sustained heavy fire from machine guns and possibly rocket-propelled grenades, targeting the force some 25 kilometers (15 miles) west of the town of Khor Abeche, United Nations forces spokesman Chris Cycmanick said Saturday.

Tanzania, which is largely peaceful and stable in a region plagued by armed conflict and rebel insurgency, is becoming more active in regional peacekeeping missions. Last year it was the first to offer to send troops to eastern Congo under what will become a brigade of U.N. peacekeepers with a mandate to combat rebels groups there. Even before the deployment becomes fully operational, the brigade — which also includes troops from Malawi and South Africa — has been threatened by Congolese M23 rebels who say they will be forced to defend themselves if they are attacked by the peacekeepers.

The attack on Tanzanian troops in Darfur was condemned by U.N. Secretary-General Ban Ki-moon, who identified the dead as being from Tanzania. A statement Saturday on behalf of Ban said the “heinous attack” was the third on U.N. forces in the region in the last three weeks. On Sunday, the U.N. Security Council also condemned the attack and called on the Sudanese government to “swiftly to investigate the incident and bring the perpetrators to justice.”

About 40 countries have contributed military personnel or police to the Darfur peacekeeping mission, dubbed UNAMID.

The peacekeeping force was established to protect civilians in Darfur, but also contributes to security for those providing humanitarian aid, verifying agreements, political reconciliation efforts and promoting human rights. It has about 16,500 troops and military observers and over 5,000 international police.

No group immediately claimed responsibility for the assault Saturday. Tribal clashes remain common in the region and some former government militias have begun taking up arms again as fighting continues over land and resources. A February report by a U.N. panel of experts said that some armed opposition groups angry about the presence of peacekeepers have called the force “a legitimate target.”

Darfur has been gripped by bloodshed since 2003 when rebels took up arms against the government in Khartoum. More than 300,000 people have been killed in the conflict. The International Criminal Court indicted Sudanese President Omar al-Bashir in 2009 on genocide and war crimes charges over the fighting in Darfur. The country split into Sudan and South Sudan in 2011.

Unrest continues in the region. About 300,000 people have fled fighting throughout Darfur in the first five months of this year, according to the U.N.